The mechanisms underlying performance on the Star Counting Test (SCT) and its nomothetic span were investigated along with the relationships between working memory capacity, fluid intelligence (Gf), speed, and school achievement. The SCT is an attention test for children that requires the alternation of forward and backward counting. The test is based on A. D. Baddeley and G. J. Hitch's (1974) model of working memory in conjunction with D. A. Norman and T. Shallice's (1986) theory of central executive functioning. Tests were administered to 1,122 boys and 1100 girls in 4th grade from 111 Dutch schools. The SCT required flexible alternation, counting speed, and sustained effort. Factor analysis showed that the SCT forms one factor with other indicators of working memory capacity. There was also a strong association between working memory capacity and Gf. The two clearly differ, however, in their relation to speed.

Summary-The Star Counting Test (XT), an attention test for children, is presented. 'lhe test is suitable for groupwise administration. It was developed within a clear theoretical framework and focuses, in contrast to many current attention tests, on accuracy rather than speed. The test requires the control and alternation of two simple processes: forward and backward counting. In a prestudy, the reliability of the test appeared satisfactory. Substantial correlations were found with the Hyperactivity scale of the Conners Teacher Rating Scale and with grades for language and arithmetic. For the main study, a large scale assessment study of attentional deficits in Dutch elementary schools, three versions of the test were constructed. All versions of the test appeared reliable and substantial correlations were observed with the Attentional Behavior Scale of the Amsterdam Child Behavior Scale, a rating scale for teachers. Furthermore, the test was able to discriminate between various childhood disorders as rated by teachers. It was concluded that the SCT exhibits some essential characteristics that are needed for the measurement of individual differences in attention. The test can be used in large scale assessment studies and might be useful as a first screening device for attentional deficits.Attention is assumed to have a wide range of influence on many aspects of cognitive functioning. An efficient and successful course of the process of knowledge acquisition, for instance, is dependent on a proper functioning of attentional control processes like selectivity, flexibility, and planful behavior. Attention is a prerequisite for learning.In schools, children with attention deficits are of great concern. According to teachers in The Netherlands, an increasing number of children suffer from attentional problems (Das-Smaal, de Leeuw & Orlebeke, 1987), and large scale assessment studies in different countries indicate that the incidence of attentional problems among children aged 6-12 is considerable (Achenbach, Verhulst, Edelbrock, Baron & Akkerhuis, 1987;McGee, Williams & Silva, 1985; Taylor & Sandberg, 1944;Verhulst & Akkerhuis, 1986;Vikan, 1985). Cross-cultural and cross-temporal comparisons of prevalence rates are, however, problematic because most of these epidemiological studies have heavily relied on teacher ratings of behavior. Often the items in the rating scales that are used, are not tied to precise behaviors, but require a judgment about the appropriateness of a behavioral category, like for instance 'impulsiveness' (Taylor, 1987). Variations in teacher ratings might therefore reflect systematic differences in the behaviors that are considered relevant to a behavioral category. Another point of concern with respect to the comparison of teacher ratings are norm differences. Taylor (1987) suggests that the 20-fold difference in the prevalence rate of hyperactivity in the U.K. and U.S.A. might be the result of a discrepancy in the thresholds of tolerance towards the behaviors that form the problem. Because of ...

This study addresses the relationship between impulsivity and lack of inhibition. Inhibition was measured bath by the interference score and by the negative priming effect in a Stroop colour-word paradigm. The negative priming effect in this paradigm is defÏned by slower naming of a target colour if this colour was the distractor in the immediately preceding trial.Por the study, a total of 210 school children were selected. These were children rated high or low by their teachers for either social or cognitive impulsivity. A reduced negative priming effect showed up with social type but not with cognitive type impulsive children. No differences were found regarding the Stroop interference score. The divergence between negative priming and interference as a measure of inhibition was discussed. Overall, the fÏndings corroborate the distinction between a cognitive and a social dimension of impulsivity.

A pilot study was carried out to investigate the relationship between exposure to lead and attention in children. The participants were 43 boys, 8 to 12 years of age, attending special schools for children with educational and/or learning problems (so called LOM schools). Children with probable causes of attentional or memory problems other than lead contamination were excluded from the study. Various aspects of attention were measured using neuropsychological tests. As an assessment of body lead burden, lead concentration in the boys' hair was measured by means of the Synchrotron Radiation-Induced X-ray Fluorescence technique (SXRF). Information was collected about variables that possibly could influence attention and/or body lead burden (confounding factors). A multiple regression analysis was used to determine the contribution of lead to variance in performance, after correction for confounding factors. The results showed that children with relatively high concentrations of lead in their hair reacted significantly slower in a simple reaction-time task than did children with relatively low concentrations of lead in their hair. In addition, the former were significantly less flexible in changing their focus of attention, even after correction for the influence of their delayed reaction time.

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